Pacific Ocean and Mauna Loa Volcano
Webcam

Mauna
Loa is the largest volcano on Earth
in terms of volume and area covered
and one of five volcanoes that form
the Island of Hawaii in the U.S.
state of Hawaii in the Pacific
Ocean. It is an active shield
volcano, with a volume estimated at
approximately 18,000 cubic miles
(75,000 km3), although its peak is
about 120 feet (37 m) lower than
that of its neighbor, Mauna Kea. The
Hawaiian name "Mauna Loa" means
"Long Mountain". Lava eruptions from
Mauna Loa are silica-poor, thus very
fluid: and as a result eruptions
tend to be non-explosive and the
volcano has relatively shallow
slopes.

The
volcano has probably been erupting
for at least 700,000 years and may
have emerged above sea level about
400,000 years ago, although the
oldest-known dated rocks do not
extend beyond 200,000 years. Its
magma comes from the Hawaii hotspot,
which has been responsible for the
creation of the Hawaiian island
chain for tens of millions of years.
The slow drift of the Pacific Plate
will eventually carry the volcano
away from the hotspot, and the
volcano will then become extinct
within 500,000 to one million years
from now.

Mauna
Loa's most recent eruption occurred
from March 24, 1984, to April 15,
1984. No recent eruptions of the
volcano have caused fatalities, but
eruptions in 1926 and 1950 destroyed
villages, and the city of Hilo is
partly built on lava flows from the
late nineteenth century. In view of
the hazards it poses to population
centers, Mauna Loa is part of the
Decade Volcanoes program, which
encourages studies of the most
dangerous volcanoes. Mauna Loa has
been intensively monitored by the
Hawaiian Volcano Observatory since
1912. Observations of the atmosphere
are undertaken at the Mauna Loa
Observatory, and of the Sun at the
Mauna Loa Solar Observatory, both
located near its summit. Hawaii
Volcanoes National Park covers the
summit and the southeastern flank of
the volcano, including a separate
volcano, Kīlauea.